(CBS News) SALEM, Va. - If the Supreme Court strikes down the Affordable Care Act this week, President Obama will have "wasted" most of his first term, presumptive Republican nominee Mitt Romney said Tuesday.

"As you know, the Supreme Court is going to be dealing with whether or not Obamacare is constitutional. If it is not - if Obamacare is not deemed constitutional -- then the first three and a half years of this president's term would have been wasted on something that has not helped the American people," Romney told a crowd of about 1,500 voters at Carter Machinery Company, one of the leading Caterpillar machine dealerships in the country.

The Affordable Care Act has been taking effect in stages, with the initial benefits focused on seniors, young people and preventive services. Romney repeated his oft-made pledge "get rid of" the law on the first day of his presidency if it is upheld by the Court. He has said he'll give every state waivers from the law.

The Supreme Court is expected to issue its ruling Thursday. On Monday, in another major ruling, it struck down most of a controversial Arizona immigration law. The decision was viewed largely as a victory for the Obama administration, but Romney used it to attack Obama for not passing immigration reform during his first year in office.

"I think all their work highlights the leadership failures of our current president," Romney said of the court, seeking to capitalize on the high-profile news.

Part of his speech focused on energy and a pledge to utilize more below-ground resources, like coal, in American energy production. The company, Carter Machinery, was owned by Caterpillar, Inc. until 2011 and has deep ties to the coal industry. Democrats attribute some of its success to the fact that it received $368,324 in federal stimulus money in 2010.